With the rising cost of energy and a concern for the environment, a means of providing efficient, low-cost lighting has become of major importance. Currently, the prior art utilizes incandescent light bulbs and fluorescent lamps.
A typical 60 watt incandescent lamp produces a light output of approximately 750 lumens, has a useful life of approximately 1000 hours and consumes approximately 60 watts of power. Fluorescent lamps, which also include Compact Fluorescent Lamps (CFLs), are highly efficient and produce a light output of approximately 900 lumens, have a useful life of approximately 10,000 hours and consume approximately 13 watts of power. The problem with fluorescent lamps and CFLs is that they are not environmentally friendly as a result of containing highly toxic mercury, which necessitates that the lamps be properly disposed.
With the development of Light Emitting Diode (LEDs), which produce “White Light” another step forward was taken. An LED is similar to a conventional PN junction diode with one advantage, the LED produces a light at the PN junction, and LEDs are much more efficient than either an incandescent lamp or a fluorescent lamp. LEDs can be operated with a voltage that ranges from 1.5 to 4.5 volts d-c, require current in milliamps and have a useful life of up to 50,000 hours. Additionally, LEDs do not typically have catastrophic failures like incandescent and fluorescent lamps. Their light output does however diminish over time. The main concern for the proper operation of LED's is not the voltage but the current that is supplied to the LEDs. A higher current produces more light output but reduces the useful life expectancy of the LEDs. Another concern is that the voltage drop across the PN junction can vary greatly even from the same batch of LEDs thereby causing them to produce more or less light output from lamp to lamp. If using LED's in clusters, they should be “matched” so that all the LEDs light with the same intensity.
The problems associated with incandescent and fluorescent lamps are solved or at least minimized by the inventive LPS.
A search of the prior art did not disclose literature or patents that read directly on the claims of the instant invention.